The invention is based on a multiphase extractor having an extraction chamber and a re-extraction chamber which are connected in their upper and lower parts by connecting channels and have distribution devices and connectors for the supply and discharge of a donor phase and an acceptor phase.
A multiphase extractor of this type can be used in the chemical, hydrometallurgical, microbiological and other sectors of industry for the separation, extraction, concentration and purification of substances.
From the technical point of view and regarding the achievable effect, the closest of the known apparatuses is the three-phase extractor described in Russian Patent Application 94-015776/26, which consists of an extraction chamber and a re-extraction chamber which are filled with the continuous phase (liquid membrane). The chambers have devices for dispersing the respective phase and are connected to one another via overflows for the circulation of the continuous phase. The overflows are in the form of connecting channels or pipes which connect the upper and lower parts of the chambers to one another. The extractor is provided with connectors for the supply and discharge of the first and second disperse phases. The first phase to be dispersed, which is the starting solution, or donor phase, and contains the substance to be removed, and the second phase to be dispersed, the acceptor phase, are each dispersed in the corresponding chamber in the form of droplets by means of a dispersion or distribution device. These droplets move through the continuous phase as a stream of droplets. Owing to the density difference in the dispersions in the first and second chambers, circulation of the continuous phase takes place through the upper and lower overflows, resulting in transfer of the extracted substance from one chamber into the other and from the donor phase into the acceptor phase. Thus, extraction with the continuous phase as extractant takes place in the first chamber, and re-extraction of the removed substance with the acceptor phase as re-extractant takes place in the second chamber.
The invention has the object of modifying the multiphase extractor to enable further possible applications in which extraction and re-extraction processes can be coupled with washing processes in a single apparatus. In particular, washing of the extractant should also be enabled here.
This object is achieved in accordance with the invention in the multiphase extractor described at the outset through the extraction chamber and re-extraction chamber being connected to one another via an intermediate washing chamber.
According to a preferred embodiment of the invention, the extraction, re-extraction and washing chambers are equipped with separation zones.
According to a preferred embodiment, the upper part of the extraction chamber is connected directly to the upper part of the re-extraction chamber.
Alternatively, the upper part of the extraction chamber can be connected directly to the lower part of the re-extraction chamber.
A further alternative consists in that the lower part of the extraction chamber is connected directly to the lower part of the re-extraction chamber.
A further refinement of the invention is characterized in that the extraction chamber and the re-extraction chamber together with the washing chamber form a single separating stage, and a series of such stages are connected in series in the form of a cascade.
The incorporation of washing chambers between the extraction and re-extraction chambers allows coupled extraction, washing and re-extraction processes to be carried out in one and the same apparatus.
The different types of connection between the extraction and re-extraction chambers provide the prerequisite for achieving different technological variants of the separation process (co-current or countercurrent flow of the extractant with the donor, washing and acceptor phases).
The connection of a plurality of separation stages, each consisting of an extraction chamber, a washing chamber and a re-extraction chamber, in series in a cascade-like arrangement allows multistage mass transfer processes to be carried out in the multiphase extractor.